PHILADELPHIA — A former Pennsylvania Turnpike chairman admitted with a felony plea today he tried to thwart an FBI probe of long-powerful state Sen. Vincent Fumo, a close friend who steered him senate funds.

Mitchell Rubin, 58, of Philadelphia will serve six months of house arrest and repay $150,000 to the state senate after pleading guilty today to felony obstruction of justice.

Rubin admits he misled FBI agents and a federal grand jury about his senate contracts and relationship with Fumo. Prosecutors allege he did little or no work to earn the $30,000 a year from the Fumo-led Senate Democratic Appropriations Committee.

Rubin's wife, longtime Fumo aide Ruth Arnao, went to trial with Fumo in a sweeping corruption case that ended last year with convictions on 139 counts. She is serving a 1-year prison term, and Fumo a 5-year term.

Rubin flies to Kentucky to visit his wife each weekend, his lawyer said.

U.S. District Judge Ronald Buckwalter, who was harshly criticized by some state residents for sentencing Fumo far below guidelines for the estimated $3.5 million fraud, said he "agonized" about whether to accept Rubin's plea agreement.

"He's getting a huge break in my mind in not going to jail," Buckwalter said. "While I'm perhaps lenient as a judge, I've always been upset by people who actually do defraud the government."